Service VME - EV Cooling Fan Noise Characteristics - Do Not Replace EV Fan- keywords brief cold coolant delay engine flare intermittent lock overspeed roar shift startup

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Changes were made in June of 2005 with the electro viscous or EV fan clutch to improve the HVAC performance in high ambient temperatures, which basically allows increased airflow in certain conditions. With this change, it is now possible, during start up, for the EV fan clutch to be engaged and the EV fan may match engine speed for about 1 minute depending on driving speeds, with a longer engagement time at lower speeds. This is dependent on the internal check valve orientation when the engine is shut off and will be intermittent. Additionally, vehicles parked nose up on a 16% or higher incline (such as vehicles coming off transport or parked on steep driveways) may have fan noise for an extended period of time. If the vehicle is not parked in these conditions, the extended fan noise should not be an issue. Do not replace EV fan clutches for these conditions, they are expected vehicle characteristics. If the fan clutch is truly operating at a speed higher than intended, a DTC P0495 or P1484 should set. Please refer to Preliminary Information PlP3637 in SI.

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Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.